ACT I A magnificent park outside the palace. Prince Siegfried is celebrating his birthday with his tutor, friends and peasants.The revelries are interrupted by Siegfried’s mother, the Queen, who is concerned about her son’s carefree lifestyle. She tells him that he must choose a bride at the royal ball the following evening. Siegfried is upset that he cannot marry for love. His friend Benno and the tutor try to lift his troubled mood. As evening falls, Benno sees a flock of swans flying overhead and suggests they go on a hunt. Siegfried and his friends take their crossbows and set off in pursuit of the swans.

ACT II That night at the lake Siegfried is transfixed by the appearance of a swan, which changes before his eyes into the princess Odette. She and her maidens are prisoners of the sorcerer Rothbart, and condemned to be swans for all but a few hours of each night. Only a vow of true love and fidelity can break the spell. Rothbart suddenly appears. Siegfried threatens to kill him but Odette intercedes – if Rothbart dies before the spell is broken, it can never be undone. As Rothbart disappears, the swan maidens fill the clearing. Siegfried breaks his crossbow, and sets about winning Odette’s trust as the two fall in love. But as dawn arrives, the evil spell draws Odette and her companions back to the lake and they are turned into swans again.

ACT III The next night in the palace ballroom. A great ball is in progress, and this evening the distracted prince is expected to choose a future consort to reign with him. None are aware of his secret love for Odette. The festivities are interrupted by the arrival of Rothbart and his retinue, which includes his daughter Odile. Strangely resembling Odette, the seductive beauty captivates Siegfried. Odette appears and attempts to warn Siegfried, but he does not see her. He then proclaims to the court that he will marry Odile, believing her to be Odette, before Rothbart shows him a magical vision of Odette. Grief-stricken and realizing his mistake, Siegfried hurries back to the lake.

ACT IV That night at the lake Odette is distraught. The swan-maidens try to comfort her. Siegfried returns to the lake and makes a passionate apology. She forgives him, but his betrayal cannot be undone. Rather than remain a swan forever, Odette chooses to die. Siegfried chooses to die with her and they leap into the lake. This breaks Rothbart’s spell over the swan maidens, causing him to lose his power over them and he dies. The lake rises from the storm and drowns Odette and Siegfried. The storm quiets, and a group of swans appears on the lake.